Recently, miniaturized satellites, such as Cube-sat nanosatellites, are increasingly widely used. The dimensions of a single nanosatellite module according to this standard are 10 cm×10 cm×10 cm. Larger satellites can also be built out of these modules. A single module normally consists of various structural elements, such as reflectors, transceivers, antennas, sensors, etc. In spite of the small dimensions, the nanosatellites are used for various tasks. Some of them require directional and steerable beam in VHF and UHF bands, as is the case when tracking ships (AIS systems), aircraft (ADS-B), and radio beacons (Argos) from space. As a rule, nanosatellites are equipped with deployable single-strip monopoly antennas (Encinas Plaza, José, Vilán J. A., Vilén, Aguado, F. Agelet, J., Barandiarán Mancheño, López Estevez, M., Martinez Fernandez, C., Sarmiento Ares, F. “Xatcobeo: Small Mechanisms for CubeSat Satellites-Antenna and Solar Array Deployment,” Proceedings of the 40th Aerospace Mechanisms Symposium, (2010), 415-430) and usually several antennas are mounted on a single satellite. When operating from a low orbit, e.g. at 700 km altitude, the field of view of a conventional non-directional satellite antenna is a circle of 5000 km diameter. The zone can contain a large multitude of devices and the signals from them will overlap in time and interfere with each other. A directional beam would reduce the field of view and likelihood of mutual interference between signals. It would also amplify the signal at the receiver. However, formation of directional and steerable radio beam in VHF and UHF bands requires a large antenna, many times exceeding the standard nanosatellite dimensions. For this reason, antennas capable of generating directional and steerable radio beams are not yet used in the current nanosatellite missions.
The U.S. patent application Ser. No. 07/902,107 disclosed a spacecraft antenna, which is a self-deploying monopoly vibrator system. The major disadvantage of this antenna design is the need for additional guiding structures and a broad transverse plane, on which the monopoly vibrators are mounted. For this reason, the antenna cannot be placed and deployed on a nanosatellite due to its structure and weight. European patent application EP20130003752 disclosed a deployable nanosatellite antenna of helical structure for UHF and VHF bands. This design allows placement of a deployable antenna in a standard-sized nanosatellite, which in the extended configuration is larger than the satellite itself or a standard type monopole nanosatellite antenna. Thus the signal is amplified, yet the direction of the radio beam cannot be changed without turning the antenna itself.
US patent publication No U.S. Pat. No. 5,313,221 discloses a phased array monopole antenna having a single layer membrane upon which plurality of antenna units are attached. Each antenna unit has a flexible curved antenna blade which bends over or springs up when the membrane is rolled or unrolled on a drum. Main disadvantage of this prior art is use of complicated unrolling means for unrolling array monopole antenna which imparts additional weight to a spacecraft and may lead to faulty unfolding.
Publication by Kelleher S. et al. “Electronic scanning for satellites” in proceedings of the National Electronics Conference, vol. 17, 1 Jan. 1961, pages 290-300, XP001387797, discloses a dipole antenna made of one or more panels of printed circuit hybrids and interconnected with coaxial lines. The antenna is deployed by deployment means such as inflation means, flares. Such antenna requires a difficult folding pattern and additional means for unfolding such antenna which may lead to faulty or difficult deployment.
Publication by J. Costantine et al: “Deployable antennas for CubeSat and space communications”, 2012 6th European Conference On Antennas And Propagation (EUCAP), 1 Mar. 2012, pages 837-840, XP055250476 discloses two UHF antenna concepts. A first antenna is a conical log spiral antenna while a second antenna is a log periodic crossed dipole antenna array. Design of these two antennas is such that they require means for deployment like a one way linear or rotary actuator. It leads to increased weight and need for additional space in the compartment of a satellite. As well as such antenna may lead to faulty or difficult deployment.
This invention seeks to circumvent the said limitations of nanosatellite antennas by proposing a phased array antenna of deployable construction made of many monopole electric vibrators that could be placed in a standard-sized nanosatellite and deployed from it. The invention makes it possible to place phased array antennas into a small satellite and to take advantage of this type of antennas, such as ability to steer the beam, simultaneous generation of several beams, amplification of desirable signals and suppression of undesirable signals.